Table 3. Results of subgroup analysis about PLR (platelet to lymphocyte ratio) and OS (overall survival) in lung cancer.

Stratified analysis	No. of studies	No. of patients	Random-effects model		Fixed-effects model		I2(%)
			HR(95% CI)	p	HR(95% CI)	p
Histology
NSCLC	9	3183	1.43(1.14–1.78)	0.002	1.34(1.18–1.51)	<0.001	60.0
SCLC	4	1221	1.10(0.76–1.58)	0.611	1.01(0.87–1.17)	0.904	77.8
Treatment
Surgery	3	2286	1.20(0.87–1.65)	0.266	1.21(1.04–1.41)	0.016	65.0
C or R	5	848	1.66(1.15–2.38)	0.007	1.61(1.30–2.00)	<0.001	58.4
Tumor stage
Early stage	2	992	2.17(0.86–5.49)	0.103	1.61(1.24–2.08)	<0.001	71.1
Late stage	5	1204	1.41(1.13–1.76)	0.021	1.41(1.19–1.68)	<0.001	33.5
Country
Western	6	841	1.64(1.32–2.04)	<0.001	1.64(1.32–2.04)	<0.001	0
Eastern	7	3767	1.19(0.93–1.51)	0.163	1.14(1.03–1.27)	0.009	80.7
Sample size
≥200	8	4004	1.29(1.02–1.64)	0.034	1.20(1.08–1.33)	<0.001	78.2
<200	5	604	1.45(0.97–2.15)	0.067	1.32(1.06–1.63)	0.012	64.9
Cut–off value
≤150	4	1222	1.22(0.82–1.81)	0.326	1.06(0.87–1.29)	0.561	59.8
150~200	6	2228	1.47(1.18–1.82)	<0.001	1.44(1.27–1.65)	<0.001	56.8
≥200	3	1158	1.20(0.69–2.11)	0.519	1.03(0.87–1.22)	0.754	84.4
HR estimate
UV	7	3101	1.53(1.37–1.72)	<0.001	1.53(1.37–1.72)	<0.001	0.5
MV	11	4294	1.29(1.05–1.59)	0.015	1.20(1.09–1.31)	<0.001	75.5

P < 0.05 is considered to be significant.

Abbreviation: PLR: platelet to lymphocyte; OS: overall survival; NSCLC: non-small cell lung cancer; SCLC: small cell lung cancer; UV: univariate analysis; MV: multivariate analysis; UV: univariate analysis; MV: multivariate analysis; HR: hazard ratio; C: chemotherapy; R: radiotherapy.